Stepping gear for the track selector in a multi-track tape recorder



June 4, 1968 WALDENBURGER ET AL 3,386,294

STEPPING GEAR FOR THE TRACK SELECTOR IN A MULTI-TRACK TAPE RECORDER Filed April 19. 1956 e I Fig.7

INVENTOR$ HERMAN/V WALOENB (JR GER PETEL SCHLEGEL ATTORNEY United States Patent 3,386,294 STEPPING GEAR FOR THE TRACK SELECTOR IN A MULTI-TRACK TAPE RECORDER Hermann Waldenburger, Pforzen, near Kaufbeuren, and Peter Schlegel, Stottwang, near Kaufbeuren, Germany, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed Apr. 19, 1966, Ser. No. 543,584 Claims priority, application Germany, Apr. 23, 1965, St 23,727 3 Claims. (Cl. 74-54) ABSTRACT OF THE DISCLOSURE An eccentric friction wheel is provided which is pivotally mounted to a swivel lever and with the aid of a spring is pressed against a tape windup reel. The body of the wheel comprises a spiral shaped groove, the beginning and end of which is joined by an S-shaped cam portion, and a guide pin lever which is pivotally mounted to the swivel lever has a guide pin which engages the groove in the friction wheel.

The present invention relates to a stepping gear for the track selector in a mult'i-tra'ck tape recorder, which steps the track selector to the next successive track after the playback of one track.

The track selector of a multi-track tape recorder, as a rule, is equipped with a positioning wheel comprising as many tooth spaces as tracks are provided on the tape. For the purpose of advancing this Wheel during the continuous playback of the tape, it is known to provide a lever mechanism which is actuated by a special electromagnet, or by an electromagnet in the apparatus which also serves other purposes. These solutions, however, are not very advantageous because either an additional electromagnet is required, or because a dual purpose electromagnet must be designed more powerful. The latter is not very suitable, especially in cases where the magnet remains on for a long period of time and, in view of the unfavorable attracting behavior, requires a considerable amount of current for the additional load.

Another disadvantage of stepping on with the aid of an electromagnet is that it is accompanied by a loud jerking noise which is rather disturbing.

The present invention provides an arrangement for avoiding these disadvantages, and proceeds from the idea of using one of the motors already in the apparatus, for actuating the track selector, and which already possesses sufficient power reserve.

The present invent-ion is characterised by the fact that an eccentric friction wheel is mounted on a two-arm swing-type lever which, by the action of a spring, is pressed against the rim of a tape windup drum, that the body of the friction wheel comprises a spiral shaped groove which, at the end, and via an S-shaped transition, is led back again to the beginning, and that a second lever, is pivoted and movable in relation to the centre axis of the friction wheel, so that it is pressed with the aid of a spring towards the centre of the axis, and engages the groove with the aid of a stud.

In extending the idea of the invention, the friction wheel at its point lying closest to the axis or shaft, is provided with a brake lining serving as the rundown brake for the tape reel.

By employing this arrangement it is possible, at little cost, to provide a practically noiseless stepping device Without additional power consumption.

'Both the construction and the mode of operation of 3,386,294 Patented June 4, 1968 an embodiment of the invent-ion will now be explained with reference to FIGS. 1 to 3, in which:

FIG. 1 shows the arrangement during the forward movement of the tape,

FIG. 2 shows the actuation of the stepping mechanism at the beginning of the fast rewind, and

FIG. 3 shows the condition at the beginning of a new forward movement of the tape reel.

Referring now to the drawing, a friction wheel S, eccentrically mounted to the lever 2, is pressed with the aid of a tension spring 4 against the inside edge of a tape reel 1. The two-arm lever 2 is pivoted on a pin 3 which is mounted to the chassis. The body of the friction wheel 5 comprises a spiral shaped groove 6, the beginning and the end of which are connected by an S-shaped cam portion 7. In the cam portion 6/7, rides a pin 8 which is mounted to a lever 9 seated on a stud 15 which, staggered in relation to the connection line between the pin 3 and t e centre of the axis 14 of the friction wheel 5, is mounted near the pin 3-. A spring 10 causes lever 9 to be pressed towards the axis 14 of the friction wheel 5.

If the reel I mounted to axis 16 is turned, as indicated by the arrow in FIG. 1, in the forward direction, then the stud 8 is positioned in the bend of the S-curve 7 facing the shaft or axis 14 of the friction wheel 5. In this way the friction Wheel is blocked and the brake-lining 11 serves as rundown brake for the reel or drum 1. If the direction, as indicated by the arrow in FIG. 2, is changed to the fast rewind, then the friction wheel 5 is turned, and the pin 8 slides in the spiral shaped curve 6. In the course of this, the end 12 of the lever 2 performs a movement in the direction as indicated by the arrow 17, because the axis 14 is shifted toward the axis 16 by the eccentrically mounted friction wheel 5. The end 12 either directly or with the aid of an intermediate hinge, engages one tooth space of the track selector (not shown) for advancing it by one step. This process is per-formed continuously during one rotation of the friction wheel 5, and without causing any noise. After the friction Wheel 5 has performed one rotation, the pin 8 will enter the bend of the S-curve lying closest to the circumference of the friction wheel 5, blocking it. The brake-lining 11 is applied to the drum or reel (FIGURE 3 solid line arrow).

If as indicated in FIGURE 3 by the dashed line arrow the drive is switched to begin the forward movement, then the pin 8 will immediately slide into the inner bend 7' of the S-shaped curve 7 and will after a short time, without sliding along groove 6 reassume the starting position, as shown in FIG. 1. This small movement, performed by the end 12 of lever 2, has no effect on the positioning of the track selector. In order to reduce the noise caused when the pin 8 meets the limit stop, an elastic bumper 13 is provided in the outer portion of the bend in the S- shaped curve 7.

While we have described above the principles of our invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of our invention, as set forth in the objects thereof and in the accompanying claims.

We claim:

1. An arrangement for advancing the track selector of a multi-track tape recorder comprising:

an eccentric friction wheel which is pivotally mounted to one end of a swivel mounted lever;

a first spring attached to said swivel lever and positioned to urge said wheel against the edge of a tape windup reel;

2. spiral-shaped groove located in the body .of said wheel, the beginning and end of which are connected by an S-shaped cam portion;

3 a guide pin lever pivotally mounted to said swivel lever, and a guide pin located in said guide pin lever for engaging said groove; and second spring connecting both said swivel and guide pin levers to force said guide pin toward the pivota-ble axis of said friction wheel, such that when said friction wheel is caused to rotate by said reel, said guide pin slides in said groove and the other end of said swivel lever is pivotally displaced for advancing the track selector by one step.

2. An arrangement according to claim 1 wherein on a portion of said friction Wheel there is provided a brake lining, such that when said guide pin is positioned in the inner bend of said S-shape'd cam portion, said friction References Cited UNITED STATES PATENTS 2,424,132 2/ 1943 Alexandersson 74-54 2,606,641 8/ 1952 Kleinschrnidt 19766 2,692,509 10/1954 Gibson 74-53 3,127,178 6/1960 Osborne et a1. 274l1 FRED C. MATTERN, JR., Primary Examiner.

wheel is blocked, and serves in conjunction with said 15 CORNETTE, Assismnl Examine!- brake lining as the run down brake for said reel. 

